The user demands on mobile devices drive the development of touch screens to, besides getting bigger and providing higher resolution, to be more durable and water proof/resistant. Since the display is representing most of the mechanical design it is quite significant that original equipment manufacturers (OEMs) are able to provide robust designs with displays that can take some hard impact and provide a rugged usability towards its users. This needs to be done without the costs of losing optical- and touch-performances and with a substantial industrial design maintaining a slim and integrated design appealing to the broad market.
However, mobile devices that are promoted as water resistant claims to be able to provide touch detection on the display even with a small amount of water on them, or at least after wiping away most of the water, but the touch detection is still quite poor.
EP 2 464 099 discloses an electronic apparatus comprising liquid detection on the surface of a display in order to turn off the entire display or the part of the display that is covered with water.
There is therefore a need for a touch detection system that allows the entire touch screen to be used while it is in a surrounding of high humidity or partially or entirely covered with water or while submerged in water and that maintains the touch resolution of the capacitive touch screen while no water or only a partial covering of water is present on the touch screen without adding any additional build height.